What exactly does the .join () method do? - Stack Overflow
I'm pretty new to Python and am completely confused by .join() which I have read is the preferred method for concatenating strings. I tried: strid = repr(595) print array.array('c', random.sample(
What is a SQL JOIN, and what are the different types?
Theta-join is analogous to a special case of inner join where the on is a theta comparison on of a column from each. Some decades after Codd defined them some textbook (s) misdefined …
LEFT JOIN vs. LEFT OUTER JOIN in SQL Server - Stack Overflow
Jan 2, 2009 · Left Join and Left Outer Join are one and the same. The former is the shorthand for the latter. The same can be said about the Right Join and Right Outer Join relationship. The …
What is the difference between JOIN and INNER JOIN?
The fact that when it says INNER JOIN, you can be sure of what it does and that it's supposed to be just that, whereas a plain JOIN will leave you, or someone else, wondering what the …
How to join (merge) data frames (inner, outer, left, right)
Cross join: merge(x = df1, y = df2, by = NULL) Just as with the inner join, you would probably want to explicitly pass "CustomerId" to R as the matching variable. I think it's almost always …
SQL JOIN where to place the WHERE condition? - Stack Overflow
1. For INNER JOIN any condition can be in a WHERE instead of an ON as long as there is no intervening OUTER JOIN. 2. When moving a LEFT JOIN condition from an ON to a WHERE …
What's the difference between INNER JOIN, LEFT JOIN, RIGHT …
INNER JOIN gets all records that are common between both tables based on the supplied ON clause. LEFT JOIN gets all records from the LEFT linked and the related record from the right …
python - How does os.path.join () work? - Stack Overflow
Dec 17, 2013 · Your second join call is not os.path.join, it is str.join. What this one does is that it joins the argument (as an iterable, meaning it can be seen as f, i, s, h) with self as the …
sql - How to do join on multiple criteria, returning all combinations ...
May 28, 2014 · I am willing to bet that this is a really simple answer as I am a noob to SQL. Given: table1 has column 1 (criteria 1) column 2 (criteria 2) column 3 (metric 1) table2 has column 1 …
What is the difference between JOIN and UNION? - Stack Overflow
May 25, 2009 · A JOIN is a means for combining fields from two tables by using values common to each. The SQL UNION operator combines the result of two or more SELECT statements.